Inclusion Criteria:

1. All patients must sign and date an Informed Consent Form consistent with ICH-GCP guidelines and local legislation prior to participation in the trial (i.e. prior to any trial procedures, including any pre-trial washout of medications and medication restrictions for pulmonary function test at Visit 1).
2. Male or female patients aged at least 18 years but not more than 75 years.
3. All patients must have at least a 5-year history of asthma at the time of enrolment into the trial and the diagnosis of asthma must have been made before the patient´s age of 40.
4. All patients must have a diagnosis of severe persistent asthma and must be symptomatic despite treatment with high, stable doses of inhaled corticosteroids and a long-acting beta adrenergic agent
5. All patients must have a history of one or more asthma exacerbation in the past year.
6. Patients must have evidence of treated, severe, persistent asthma in postbronchodilatory pulmonary function tests.
7. Patients should be never-smokers or ex-smokers who stopped smoking at least one year prior to enrolment and who have a smoking history of less than 10 pack years
8. Patients must be able to use the Respimat® inhaler correctly
9. Patients must be able to perform all trial related procedures including technically acceptable pulmonary function tests and use of the electronic diary/peak flow meter.

Exclusion Criteria:

1. Patients with a significant disease other than asthma. A significant disease is defined as a disease which, in the opinion of the investigator, may (i) put the patient at risk because of participation in the trial, or (ii) influence the results of the trial, or (iii) cause concern regarding the patient´s ability to participate in the trial.
2. Patients with clinically relevant abnormal screening haematology or blood chemistry.
3. Patients with a recent history (i.e. six months or less) of myocardial infarction, hospitalisation for cardiac failure during the past year, any unstable or life threatening cardiac arrhythmia or cardiac arrhythmia requiring intervention or a change in drug therapy within the past year, known active tuberculosis, malignancy for which the patient has undergone resection, radiation therapy or chemotherapy within the last five years (treated basal cell carcinoma allowed), lung diseases other than asthma (e.g. COPD), significant alcohol or drug abuse within the past two years, patients who have undergone thoracotomy with pulmonary resection. Patients with a history of thoracotomy for other reasons should be evaluated as per exclusion criterion No. 1.
4. Patients who are currently in a pulmonary rehabilitation program or have completed a pulmonary rehabilitation program in the 6 weeks prior to the screening visit (Visit 1).
5. Patients using oral corticosteroid medication at stable doses exceeding 5 mg prednisolone or prednisolone equivalent every day or 10 mg prednisolone or prednisolone equivalent every second day.
6. Patients with known hypersensitivity to anticholinergic drugs, BAC, EDTA or any other components of the tiotropium inhalation solution.
7. Pregnant or nursing women or women of childbearing potential not using a highly effective method of birth control. Female patients will be considered to be of childbearing potential unless surgically sterilised by hysterectomy or bilateral tubal ligation/salpingectomy, or post-menopausal for at least two years.
8. Patients who have taken an investigational drug within four weeks or six half-lives (whichever is greater) prior to Visit 1.
9. Patients who have been treated with the long-acting anticholinergic tiotropium (Spiriva®), beta-blocker medication, oral beta-adrenergics, other non-approved and according to international guidelines not recommended ´experimental´ drugs for routine asthma therapy (e.g. TNF-alpha blockers, methotrexate, cyclosporin) within four weeks prior to the Screening Visit (Visit 1) or during the screening period.
10. Patients with any asthma exacerbation or respiratory tract infection in the four weeks prior to the trial.
11. Patients who have previously been randomised in this trial or in the respective twin trial (205.416 versus 205.417) or are currently participating in another trial.
12. Patients with a known narrow-angle glaucoma.

Note:

As with other anticholinergic drugs, tiotropium should be used with caution in patients with prostatic hyperplasia or bladder neck obstruction.

As with all predominantly renally excreted drugs, patients with moderate to severe renal impairment (known creatinine clearance of <= 50 mL/min) treated with tiotropium should be monitored closely.